It's not always possible to install Omeka on a VPS or other dedicated server. Sometimes you just have to make do with shared web hosting and all of the caveats that come with that.
These are some collected notes about troubleshooting Omeka installation on shared hosting based on some of my own trial and error and some useful responses from the kind people on the Omeka support forums.
The full requirements for installing Omeka available here but it's the mod_rewrite and ImageMagick ones that can be particular bugbears.
There are a list of 'Hosting suggestions' on the Omeka site to help spare you some of this pain but they are largely US-based and focused on academic institutions.
Enable development mode
The first step in troubleshooting is to know what the trouble is that you're .. ummm .. shooting. You can enable error reporting on Omeka by uncommenting the relevant line in the .htaccess file in your root directory
SetEnv APPLICATION_ENV development
ImageMagick is required by Omeka for resizing and processing images and other file uploads. You can install Omeka but it requires shell access to the server which isn't available on a lot of shared hosting (Webfaction is the only exception that springs to mind).
First, if you have ImageMagick installed it a) has to be the executable version and b) you need to know the location so you can add this to the admin settings. This is usually /usr/bin but not always.
You can check the directory path is added correctly from the Admin settings page
If you're on shared hosting and ImageMagick either isn't installed or otherwise isn't working, you can try using the PHP extension instead of the executable version of ImageMagick. This is via the imagick PECL package that can be installed from cPanel.
You'll need to update the configuration to bypass the expected ImageMagick setup.
In the application/config/config.ini file, uncomment the line and change it from:
fileDerivatives.strategy = "Omeka_File_Derivative_Strategy_ExternalImageMagick"
fileDerivatives.strategy = "Omeka_File_Derivative_Strategy_Imagick"
This will remove the directory path option from the settings page but will allow you to upload files to items in your Omeka collection.
Too many redirects
Another issue you might encounter is that ol' 'too many redirects ' loop when trying to access the installer.
This can usually be resolved by ensuring there is an .htaccess file in the installation directory as well as the site's root folder:
<Files install.php> Allow from all </Files> <Files mod-rewrite.php> Allow from all </Files> <Files check-mod-rewrite.html> Allow from all </Files> # This allows us to verify that mod_rewrite is enabled <IfModule mod_rewrite.c> RewriteEngine On # If know that mod_rewrite is enabled, but you are still getting mod_rewrite errors, # uncomment the line below and replace "/install/" with your install directory. # RewriteBase /install/ RewriteRule ^check-mod-rewrite([^/]*)\.html$ mod-rewrite.php?enabled=true [L] </IfModule>